Pull target not working
I'm not sure about your problem, it seems to work fine, the Pole Target is supposed to control the orientation of your knee, not its position in the 3D space, to move your leg you need to have a controller behind the foot and choose it as the Target in the IK Constraint. To be complete, this Target controller needs to be deparented, you must disable its Deform option in the Bone menu, and you need to parent the foot to it.